Actually this verse is covering a lot of ground. No doubt Alma explained the details to Corianton so that he would know that the Fall exposed Adam and Eve to a vast array of new feelings and new instincts. God's task was to teach the first parents how to cope with these feelings and keep them under control. During earth life they had to learn the difference between good and evil through actual experience. Of course the tree of life would have nullified these feelings and brought the learning experience to a screeching halt. That is why the flaming sword had to guard the way to the tree of life so Adam and Eve would not be tempted to partake of it.